2 mainmenu "Linux Kernel Configuration for x86"
6 bool "64-bit kernel" if ARCH = "x86"
7 default ARCH = "x86_64"
9 Say yes to build a 64-bit kernel - formerly known as x86_64
10 Say no to build a 32-bit kernel - formerly known as i386
21 select HAVE_AOUT if X86_32
24 select HAVE_UNSTABLE_SCHED_CLOCK
27 select HAVE_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
31 select HAVE_KRETPROBES
32 select HAVE_FTRACE_MCOUNT_RECORD
33 select HAVE_DYNAMIC_FTRACE
34 select HAVE_FUNCTION_TRACER
35 select HAVE_FUNCTION_GRAPH_TRACER
36 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
37 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
40 select HAVE_ARCH_TRACEHOOK
41 select HAVE_GENERIC_DMA_COHERENT if X86_32
42 select HAVE_EFFICIENT_UNALIGNED_ACCESS
43 select USER_STACKTRACE_SUPPORT
44 select HAVE_KERNEL_GZIP
45 select HAVE_KERNEL_BZIP2
46 select HAVE_KERNEL_LZMA
50 default "arch/x86/configs/i386_defconfig" if X86_32
51 default "arch/x86/configs/x86_64_defconfig" if X86_64
56 config GENERIC_CMOS_UPDATE
59 config CLOCKSOURCE_WATCHDOG
62 config GENERIC_CLOCKEVENTS
65 config GENERIC_CLOCKEVENTS_BROADCAST
67 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
69 config LOCKDEP_SUPPORT
72 config STACKTRACE_SUPPORT
75 config HAVE_LATENCYTOP_SUPPORT
78 config FAST_CMPXCHG_LOCAL
91 config GENERIC_ISA_DMA
100 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
102 config GENERIC_BUG_RELATIVE_POINTERS
105 config GENERIC_HWEIGHT
111 config ARCH_MAY_HAVE_PC_FDC
114 config RWSEM_GENERIC_SPINLOCK
117 config RWSEM_XCHGADD_ALGORITHM
120 config ARCH_HAS_CPU_IDLE_WAIT
123 config GENERIC_CALIBRATE_DELAY
126 config GENERIC_TIME_VSYSCALL
130 config ARCH_HAS_CPU_RELAX
133 config ARCH_HAS_DEFAULT_IDLE
136 config ARCH_HAS_CACHE_LINE_SIZE
139 config HAVE_SETUP_PER_CPU_AREA
142 config HAVE_DYNAMIC_PER_CPU_AREA
145 config HAVE_CPUMASK_OF_CPU_MAP
148 config ARCH_HIBERNATION_POSSIBLE
151 config ARCH_SUSPEND_POSSIBLE
158 config ARCH_POPULATES_NODE_MAP
165 config ARCH_SUPPORTS_OPTIMIZED_INLINING
168 # Use the generic interrupt handling code in kernel/irq/:
169 config GENERIC_HARDIRQS
173 config GENERIC_IRQ_PROBE
177 config GENERIC_PENDING_IRQ
179 depends on GENERIC_HARDIRQS && SMP
182 config USE_GENERIC_SMP_HELPERS
188 depends on X86_32 && SMP
192 depends on X86_64 && SMP
199 config X86_TRAMPOLINE
201 depends on SMP || (64BIT && ACPI_SLEEP)
204 config X86_32_LAZY_GS
206 depends on X86_32 && !CC_STACKPROTECTOR
210 source "init/Kconfig"
211 source "kernel/Kconfig.freezer"
213 menu "Processor type and features"
215 source "kernel/time/Kconfig"
218 bool "Symmetric multi-processing support"
220 This enables support for systems with more than one CPU. If you have
221 a system with only one CPU, like most personal computers, say N. If
222 you have a system with more than one CPU, say Y.
224 If you say N here, the kernel will run on single and multiprocessor
225 machines, but will use only one CPU of a multiprocessor machine. If
226 you say Y here, the kernel will run on many, but not all,
227 singleprocessor machines. On a singleprocessor machine, the kernel
228 will run faster if you say N here.
230 Note that if you say Y here and choose architecture "586" or
231 "Pentium" under "Processor family", the kernel will not work on 486
232 architectures. Similarly, multiprocessor kernels for the "PPro"
233 architecture may not work on all Pentium based boards.
235 People using multiprocessor machines who say Y here should also say
236 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
237 Management" code will be disabled if you say Y here.
239 See also <file:Documentation/i386/IO-APIC.txt>,
240 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
241 <http://www.tldp.org/docs.html#howto>.
243 If you don't know what to do here, say N.
246 bool "Support x2apic"
247 depends on X86_LOCAL_APIC && X86_64
249 This enables x2apic support on CPUs that have this feature.
251 This allows 32-bit apic IDs (so it can support very large systems),
252 and accesses the local apic via MSRs not via mmio.
254 ( On certain CPU models you may need to enable INTR_REMAP too,
255 to get functional x2apic mode. )
257 If you don't know what to do here, say N.
260 bool "Support sparse irq numbering"
261 depends on PCI_MSI || HT_IRQ
263 This enables support for sparse irqs. This is useful for distro
264 kernels that want to define a high CONFIG_NR_CPUS value but still
265 want to have low kernel memory footprint on smaller machines.
267 ( Sparse IRQs can also be beneficial on NUMA boxes, as they spread
268 out the irq_desc[] array in a more NUMA-friendly way. )
270 If you don't know what to do here, say N.
272 config NUMA_MIGRATE_IRQ_DESC
273 bool "Move irq desc when changing irq smp_affinity"
274 depends on SPARSE_IRQ && NUMA
277 This enables moving irq_desc to cpu/node that irq will use handled.
279 If you don't know what to do here, say N.
282 bool "Enable MPS table" if ACPI
284 depends on X86_LOCAL_APIC
286 For old smp systems that do not have proper acpi support. Newer systems
287 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
290 bool "Support for big SMP systems with more than 8 CPUs"
291 depends on X86_32 && SMP
293 This option is needed for the systems that have more than 8 CPUs
296 config X86_EXTENDED_PLATFORM
297 bool "Support for extended (non-PC) x86 platforms"
300 If you disable this option then the kernel will only support
301 standard PC platforms. (which covers the vast majority of
304 If you enable this option then you'll be able to select support
305 for the following (non-PC) 32 bit x86 platforms:
309 SGI 320/540 (Visual Workstation)
310 Summit/EXA (IBM x440)
311 Unisys ES7000 IA32 series
313 If you have one of these systems, or if you want to build a
314 generic distribution kernel, say Y here - otherwise say N.
318 config X86_EXTENDED_PLATFORM
319 bool "Support for extended (non-PC) x86 platforms"
322 If you disable this option then the kernel will only support
323 standard PC platforms. (which covers the vast majority of
326 If you enable this option then you'll be able to select support
327 for the following (non-PC) 64 bit x86 platforms:
331 If you have one of these systems, or if you want to build a
332 generic distribution kernel, say Y here - otherwise say N.
334 # This is an alphabetically sorted list of 64 bit extended platforms
335 # Please maintain the alphabetic order if and when there are additions
340 depends on X86_64 && PCI
341 depends on X86_EXTENDED_PLATFORM
343 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
344 supposed to run on these EM64T-based machines. Only choose this option
345 if you have one of these machines.
348 bool "SGI Ultraviolet"
350 depends on X86_EXTENDED_PLATFORM
353 This option is needed in order to support SGI Ultraviolet systems.
354 If you don't have one of these, you should say N here.
356 # Following is an alphabetically sorted list of 32 bit extended platforms
357 # Please maintain the alphabetic order if and when there are additions
362 depends on X86_EXTENDED_PLATFORM
364 Select this for an AMD Elan processor.
366 Do not use this option for K6/Athlon/Opteron processors!
368 If unsure, choose "PC-compatible" instead.
371 bool "RDC R-321x SoC"
373 depends on X86_EXTENDED_PLATFORM
375 select X86_REBOOTFIXUPS
377 This option is needed for RDC R-321x system-on-chip, also known
379 If you don't have one of these chips, you should say N here.
381 config X86_32_NON_STANDARD
382 bool "Support non-standard 32-bit SMP architectures"
383 depends on X86_32 && SMP
384 depends on X86_EXTENDED_PLATFORM
386 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
387 subarchitectures. It is intended for a generic binary kernel.
388 if you select them all, kernel will probe it one by one. and will
391 # Alphabetically sorted list of Non standard 32 bit platforms
394 bool "NUMAQ (IBM/Sequent)"
395 depends on X86_32_NON_STANDARD
399 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
400 NUMA multiquad box. This changes the way that processors are
401 bootstrapped, and uses Clustered Logical APIC addressing mode instead
402 of Flat Logical. You will need a new lynxer.elf file to flash your
403 firmware with - send email to <Martin.Bligh@us.ibm.com>.
406 bool "SGI 320/540 (Visual Workstation)"
407 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
408 depends on X86_32_NON_STANDARD
410 The SGI Visual Workstation series is an IA32-based workstation
411 based on SGI systems chips with some legacy PC hardware attached.
413 Say Y here to create a kernel to run on the SGI 320 or 540.
415 A kernel compiled for the Visual Workstation will run on general
416 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
419 bool "Summit/EXA (IBM x440)"
420 depends on X86_32_NON_STANDARD
422 This option is needed for IBM systems that use the Summit/EXA chipset.
423 In particular, it is needed for the x440.
426 bool "Unisys ES7000 IA32 series"
427 depends on X86_32_NON_STANDARD && X86_BIGSMP
429 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
430 supposed to run on an IA32-based Unisys ES7000 system.
432 config SCHED_OMIT_FRAME_POINTER
434 prompt "Single-depth WCHAN output"
437 Calculate simpler /proc/<PID>/wchan values. If this option
438 is disabled then wchan values will recurse back to the
439 caller function. This provides more accurate wchan values,
440 at the expense of slightly more scheduling overhead.
442 If in doubt, say "Y".
444 menuconfig PARAVIRT_GUEST
445 bool "Paravirtualized guest support"
447 Say Y here to get to see options related to running Linux under
448 various hypervisors. This option alone does not add any kernel code.
450 If you say N, all options in this submenu will be skipped and disabled.
454 source "arch/x86/xen/Kconfig"
457 bool "VMI Guest support"
461 VMI provides a paravirtualized interface to the VMware ESX server
462 (it could be used by other hypervisors in theory too, but is not
463 at the moment), by linking the kernel to a GPL-ed ROM module
464 provided by the hypervisor.
467 bool "KVM paravirtualized clock"
469 select PARAVIRT_CLOCK
471 Turning on this option will allow you to run a paravirtualized clock
472 when running over the KVM hypervisor. Instead of relying on a PIT
473 (or probably other) emulation by the underlying device model, the host
474 provides the guest with timing infrastructure such as time of day, and
478 bool "KVM Guest support"
481 This option enables various optimizations for running under the KVM
484 source "arch/x86/lguest/Kconfig"
487 bool "Enable paravirtualization code"
489 This changes the kernel so it can modify itself when it is run
490 under a hypervisor, potentially improving performance significantly
491 over full virtualization. However, when run without a hypervisor
492 the kernel is theoretically slower and slightly larger.
494 config PARAVIRT_CLOCK
500 config PARAVIRT_DEBUG
501 bool "paravirt-ops debugging"
502 depends on PARAVIRT && DEBUG_KERNEL
504 Enable to debug paravirt_ops internals. Specifically, BUG if
505 a paravirt_op is missing when it is called.
510 This option adds a kernel parameter 'memtest', which allows memtest
512 memtest=0, mean disabled; -- default
513 memtest=1, mean do 1 test pattern;
515 memtest=4, mean do 4 test patterns.
516 If you are unsure how to answer this question, answer N.
518 config X86_SUMMIT_NUMA
520 depends on X86_32 && NUMA && X86_32_NON_STANDARD
522 config X86_CYCLONE_TIMER
524 depends on X86_32_NON_STANDARD
526 source "arch/x86/Kconfig.cpu"
530 prompt "HPET Timer Support" if X86_32
532 Use the IA-PC HPET (High Precision Event Timer) to manage
533 time in preference to the PIT and RTC, if a HPET is
535 HPET is the next generation timer replacing legacy 8254s.
536 The HPET provides a stable time base on SMP
537 systems, unlike the TSC, but it is more expensive to access,
538 as it is off-chip. You can find the HPET spec at
539 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
541 You can safely choose Y here. However, HPET will only be
542 activated if the platform and the BIOS support this feature.
543 Otherwise the 8254 will be used for timing services.
545 Choose N to continue using the legacy 8254 timer.
547 config HPET_EMULATE_RTC
549 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
551 # Mark as embedded because too many people got it wrong.
552 # The code disables itself when not needed.
555 bool "Enable DMI scanning" if EMBEDDED
557 Enabled scanning of DMI to identify machine quirks. Say Y
558 here unless you have verified that your setup is not
559 affected by entries in the DMI blacklist. Required by PNP
563 bool "GART IOMMU support" if EMBEDDED
567 depends on X86_64 && PCI
569 Support for full DMA access of devices with 32bit memory access only
570 on systems with more than 3GB. This is usually needed for USB,
571 sound, many IDE/SATA chipsets and some other devices.
572 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
573 based hardware IOMMU and a software bounce buffer based IOMMU used
574 on Intel systems and as fallback.
575 The code is only active when needed (enough memory and limited
576 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
580 bool "IBM Calgary IOMMU support"
582 depends on X86_64 && PCI && EXPERIMENTAL
584 Support for hardware IOMMUs in IBM's xSeries x366 and x460
585 systems. Needed to run systems with more than 3GB of memory
586 properly with 32-bit PCI devices that do not support DAC
587 (Double Address Cycle). Calgary also supports bus level
588 isolation, where all DMAs pass through the IOMMU. This
589 prevents them from going anywhere except their intended
590 destination. This catches hard-to-find kernel bugs and
591 mis-behaving drivers and devices that do not use the DMA-API
592 properly to set up their DMA buffers. The IOMMU can be
593 turned off at boot time with the iommu=off parameter.
594 Normally the kernel will make the right choice by itself.
597 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
599 prompt "Should Calgary be enabled by default?"
600 depends on CALGARY_IOMMU
602 Should Calgary be enabled by default? if you choose 'y', Calgary
603 will be used (if it exists). If you choose 'n', Calgary will not be
604 used even if it exists. If you choose 'n' and would like to use
605 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
609 bool "AMD IOMMU support"
612 depends on X86_64 && PCI && ACPI
614 With this option you can enable support for AMD IOMMU hardware in
615 your system. An IOMMU is a hardware component which provides
616 remapping of DMA memory accesses from devices. With an AMD IOMMU you
617 can isolate the the DMA memory of different devices and protect the
618 system from misbehaving device drivers or hardware.
620 You can find out if your system has an AMD IOMMU if you look into
621 your BIOS for an option to enable it or if you have an IVRS ACPI
624 config AMD_IOMMU_STATS
625 bool "Export AMD IOMMU statistics to debugfs"
629 This option enables code in the AMD IOMMU driver to collect various
630 statistics about whats happening in the driver and exports that
631 information to userspace via debugfs.
634 # need this always selected by IOMMU for the VIA workaround
638 Support for software bounce buffers used on x86-64 systems
639 which don't have a hardware IOMMU (e.g. the current generation
640 of Intel's x86-64 CPUs). Using this PCI devices which can only
641 access 32-bits of memory can be used on systems with more than
642 3 GB of memory. If unsure, say Y.
645 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
648 def_bool (AMD_IOMMU || DMAR)
651 bool "Configure Maximum number of SMP Processors and NUMA Nodes"
652 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
653 select CPUMASK_OFFSTACK
656 Configure maximum number of CPUS and NUMA Nodes for this architecture.
660 int "Maximum number of CPUs" if SMP && !MAXSMP
661 range 2 512 if SMP && !MAXSMP
663 default "4096" if MAXSMP
664 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
667 This allows you to specify the maximum number of CPUs which this
668 kernel will support. The maximum supported value is 512 and the
669 minimum value which makes sense is 2.
671 This is purely to save memory - each supported CPU adds
672 approximately eight kilobytes to the kernel image.
675 bool "SMT (Hyperthreading) scheduler support"
678 SMT scheduler support improves the CPU scheduler's decision making
679 when dealing with Intel Pentium 4 chips with HyperThreading at a
680 cost of slightly increased overhead in some places. If unsure say
685 prompt "Multi-core scheduler support"
688 Multi-core scheduler support improves the CPU scheduler's decision
689 making when dealing with multi-core CPU chips at a cost of slightly
690 increased overhead in some places. If unsure say N here.
692 source "kernel/Kconfig.preempt"
695 bool "Local APIC support on uniprocessors"
696 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
698 A local APIC (Advanced Programmable Interrupt Controller) is an
699 integrated interrupt controller in the CPU. If you have a single-CPU
700 system which has a processor with a local APIC, you can say Y here to
701 enable and use it. If you say Y here even though your machine doesn't
702 have a local APIC, then the kernel will still run with no slowdown at
703 all. The local APIC supports CPU-generated self-interrupts (timer,
704 performance counters), and the NMI watchdog which detects hard
708 bool "IO-APIC support on uniprocessors"
709 depends on X86_UP_APIC
711 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
712 SMP-capable replacement for PC-style interrupt controllers. Most
713 SMP systems and many recent uniprocessor systems have one.
715 If you have a single-CPU system with an IO-APIC, you can say Y here
716 to use it. If you say Y here even though your machine doesn't have
717 an IO-APIC, then the kernel will still run with no slowdown at all.
719 config X86_LOCAL_APIC
721 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
725 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
727 config X86_VISWS_APIC
729 depends on X86_32 && X86_VISWS
731 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
732 bool "Reroute for broken boot IRQs"
734 depends on X86_IO_APIC
736 This option enables a workaround that fixes a source of
737 spurious interrupts. This is recommended when threaded
738 interrupt handling is used on systems where the generation of
739 superfluous "boot interrupts" cannot be disabled.
741 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
742 entry in the chipset's IO-APIC is masked (as, e.g. the RT
743 kernel does during interrupt handling). On chipsets where this
744 boot IRQ generation cannot be disabled, this workaround keeps
745 the original IRQ line masked so that only the equivalent "boot
746 IRQ" is delivered to the CPUs. The workaround also tells the
747 kernel to set up the IRQ handler on the boot IRQ line. In this
748 way only one interrupt is delivered to the kernel. Otherwise
749 the spurious second interrupt may cause the kernel to bring
750 down (vital) interrupt lines.
752 Only affects "broken" chipsets. Interrupt sharing may be
753 increased on these systems.
756 bool "Machine Check Exception"
758 Machine Check Exception support allows the processor to notify the
759 kernel if it detects a problem (e.g. overheating, component failure).
760 The action the kernel takes depends on the severity of the problem,
761 ranging from a warning message on the console, to halting the machine.
762 Your processor must be a Pentium or newer to support this - check the
763 flags in /proc/cpuinfo for mce. Note that some older Pentium systems
764 have a design flaw which leads to false MCE events - hence MCE is
765 disabled on all P5 processors, unless explicitly enabled with "mce"
766 as a boot argument. Similarly, if MCE is built in and creates a
767 problem on some new non-standard machine, you can boot with "nomce"
768 to disable it. MCE support simply ignores non-MCE processors like
769 the 386 and 486, so nearly everyone can say Y here.
773 prompt "Intel MCE features"
774 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
776 Additional support for intel specific MCE features such as
781 prompt "AMD MCE features"
782 depends on X86_64 && X86_MCE && X86_LOCAL_APIC
784 Additional support for AMD specific MCE features such as
785 the DRAM Error Threshold.
787 config X86_MCE_THRESHOLD
788 depends on X86_MCE_AMD || X86_MCE_INTEL
792 config X86_MCE_NONFATAL
793 tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
794 depends on X86_32 && X86_MCE
796 Enabling this feature starts a timer that triggers every 5 seconds which
797 will look at the machine check registers to see if anything happened.
798 Non-fatal problems automatically get corrected (but still logged).
799 Disable this if you don't want to see these messages.
800 Seeing the messages this option prints out may be indicative of dying
801 or out-of-spec (ie, overclocked) hardware.
802 This option only does something on certain CPUs.
803 (AMD Athlon/Duron and Intel Pentium 4)
805 config X86_MCE_P4THERMAL
806 bool "check for P4 thermal throttling interrupt."
807 depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
809 Enabling this feature will cause a message to be printed when the P4
810 enters thermal throttling.
813 bool "Enable VM86 support" if EMBEDDED
817 This option is required by programs like DOSEMU to run 16-bit legacy
818 code on X86 processors. It also may be needed by software like
819 XFree86 to initialize some video cards via BIOS. Disabling this
820 option saves about 6k.
823 tristate "Toshiba Laptop support"
826 This adds a driver to safely access the System Management Mode of
827 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
828 not work on models with a Phoenix BIOS. The System Management Mode
829 is used to set the BIOS and power saving options on Toshiba portables.
831 For information on utilities to make use of this driver see the
832 Toshiba Linux utilities web site at:
833 <http://www.buzzard.org.uk/toshiba/>.
835 Say Y if you intend to run this kernel on a Toshiba portable.
839 tristate "Dell laptop support"
841 This adds a driver to safely access the System Management Mode
842 of the CPU on the Dell Inspiron 8000. The System Management Mode
843 is used to read cpu temperature and cooling fan status and to
844 control the fans on the I8K portables.
846 This driver has been tested only on the Inspiron 8000 but it may
847 also work with other Dell laptops. You can force loading on other
848 models by passing the parameter `force=1' to the module. Use at
851 For information on utilities to make use of this driver see the
852 I8K Linux utilities web site at:
853 <http://people.debian.org/~dz/i8k/>
855 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
858 config X86_REBOOTFIXUPS
859 bool "Enable X86 board specific fixups for reboot"
862 This enables chipset and/or board specific fixups to be done
863 in order to get reboot to work correctly. This is only needed on
864 some combinations of hardware and BIOS. The symptom, for which
865 this config is intended, is when reboot ends with a stalled/hung
868 Currently, the only fixup is for the Geode machines using
869 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
871 Say Y if you want to enable the fixup. Currently, it's safe to
872 enable this option even if you don't need it.
876 tristate "/dev/cpu/microcode - microcode support"
879 If you say Y here, you will be able to update the microcode on
880 certain Intel and AMD processors. The Intel support is for the
881 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
882 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
883 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
884 You will obviously need the actual microcode binary data itself
885 which is not shipped with the Linux kernel.
887 This option selects the general module only, you need to select
888 at least one vendor specific module as well.
890 To compile this driver as a module, choose M here: the
891 module will be called microcode.
893 config MICROCODE_INTEL
894 bool "Intel microcode patch loading support"
899 This options enables microcode patch loading support for Intel
902 For latest news and information on obtaining all the required
903 Intel ingredients for this driver, check:
904 <http://www.urbanmyth.org/microcode/>.
907 bool "AMD microcode patch loading support"
911 If you select this option, microcode patch loading support for AMD
912 processors will be enabled.
914 config MICROCODE_OLD_INTERFACE
919 tristate "/dev/cpu/*/msr - Model-specific register support"
921 This device gives privileged processes access to the x86
922 Model-Specific Registers (MSRs). It is a character device with
923 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
924 MSR accesses are directed to a specific CPU on multi-processor
928 tristate "/dev/cpu/*/cpuid - CPU information support"
930 This device gives processes access to the x86 CPUID instruction to
931 be executed on a specific processor. It is a character device
932 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
936 prompt "High Memory Support"
937 default HIGHMEM4G if !X86_NUMAQ
938 default HIGHMEM64G if X86_NUMAQ
943 depends on !X86_NUMAQ
945 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
946 However, the address space of 32-bit x86 processors is only 4
947 Gigabytes large. That means that, if you have a large amount of
948 physical memory, not all of it can be "permanently mapped" by the
949 kernel. The physical memory that's not permanently mapped is called
952 If you are compiling a kernel which will never run on a machine with
953 more than 1 Gigabyte total physical RAM, answer "off" here (default
954 choice and suitable for most users). This will result in a "3GB/1GB"
955 split: 3GB are mapped so that each process sees a 3GB virtual memory
956 space and the remaining part of the 4GB virtual memory space is used
957 by the kernel to permanently map as much physical memory as
960 If the machine has between 1 and 4 Gigabytes physical RAM, then
963 If more than 4 Gigabytes is used then answer "64GB" here. This
964 selection turns Intel PAE (Physical Address Extension) mode on.
965 PAE implements 3-level paging on IA32 processors. PAE is fully
966 supported by Linux, PAE mode is implemented on all recent Intel
967 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
968 then the kernel will not boot on CPUs that don't support PAE!
970 The actual amount of total physical memory will either be
971 auto detected or can be forced by using a kernel command line option
972 such as "mem=256M". (Try "man bootparam" or see the documentation of
973 your boot loader (lilo or loadlin) about how to pass options to the
974 kernel at boot time.)
976 If unsure, say "off".
980 depends on !X86_NUMAQ
982 Select this if you have a 32-bit processor and between 1 and 4
983 gigabytes of physical RAM.
987 depends on !M386 && !M486
990 Select this if you have a 32-bit processor and more than 4
991 gigabytes of physical RAM.
996 depends on EXPERIMENTAL
997 prompt "Memory split" if EMBEDDED
1001 Select the desired split between kernel and user memory.
1003 If the address range available to the kernel is less than the
1004 physical memory installed, the remaining memory will be available
1005 as "high memory". Accessing high memory is a little more costly
1006 than low memory, as it needs to be mapped into the kernel first.
1007 Note that increasing the kernel address space limits the range
1008 available to user programs, making the address space there
1009 tighter. Selecting anything other than the default 3G/1G split
1010 will also likely make your kernel incompatible with binary-only
1013 If you are not absolutely sure what you are doing, leave this
1017 bool "3G/1G user/kernel split"
1018 config VMSPLIT_3G_OPT
1020 bool "3G/1G user/kernel split (for full 1G low memory)"
1022 bool "2G/2G user/kernel split"
1023 config VMSPLIT_2G_OPT
1025 bool "2G/2G user/kernel split (for full 2G low memory)"
1027 bool "1G/3G user/kernel split"
1032 default 0xB0000000 if VMSPLIT_3G_OPT
1033 default 0x80000000 if VMSPLIT_2G
1034 default 0x78000000 if VMSPLIT_2G_OPT
1035 default 0x40000000 if VMSPLIT_1G
1041 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1044 bool "PAE (Physical Address Extension) Support"
1045 depends on X86_32 && !HIGHMEM4G
1047 PAE is required for NX support, and furthermore enables
1048 larger swapspace support for non-overcommit purposes. It
1049 has the cost of more pagetable lookup overhead, and also
1050 consumes more pagetable space per process.
1052 config ARCH_PHYS_ADDR_T_64BIT
1053 def_bool X86_64 || X86_PAE
1055 config DIRECT_GBPAGES
1056 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1060 Allow the kernel linear mapping to use 1GB pages on CPUs that
1061 support it. This can improve the kernel's performance a tiny bit by
1062 reducing TLB pressure. If in doubt, say "Y".
1064 # Common NUMA Features
1066 bool "Numa Memory Allocation and Scheduler Support"
1068 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1069 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1071 Enable NUMA (Non Uniform Memory Access) support.
1073 The kernel will try to allocate memory used by a CPU on the
1074 local memory controller of the CPU and add some more
1075 NUMA awareness to the kernel.
1077 For 64-bit this is recommended if the system is Intel Core i7
1078 (or later), AMD Opteron, or EM64T NUMA.
1080 For 32-bit this is only needed on (rare) 32-bit-only platforms
1081 that support NUMA topologies, such as NUMAQ / Summit, or if you
1082 boot a 32-bit kernel on a 64-bit NUMA platform.
1084 Otherwise, you should say N.
1086 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1087 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1091 prompt "Old style AMD Opteron NUMA detection"
1092 depends on X86_64 && NUMA && PCI
1094 Enable K8 NUMA node topology detection. You should say Y here if
1095 you have a multi processor AMD K8 system. This uses an old
1096 method to read the NUMA configuration directly from the builtin
1097 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1098 instead, which also takes priority if both are compiled in.
1100 config X86_64_ACPI_NUMA
1102 prompt "ACPI NUMA detection"
1103 depends on X86_64 && NUMA && ACPI && PCI
1106 Enable ACPI SRAT based node topology detection.
1108 # Some NUMA nodes have memory ranges that span
1109 # other nodes. Even though a pfn is valid and
1110 # between a node's start and end pfns, it may not
1111 # reside on that node. See memmap_init_zone()
1113 config NODES_SPAN_OTHER_NODES
1115 depends on X86_64_ACPI_NUMA
1118 bool "NUMA emulation"
1119 depends on X86_64 && NUMA
1121 Enable NUMA emulation. A flat machine will be split
1122 into virtual nodes when booted with "numa=fake=N", where N is the
1123 number of nodes. This is only useful for debugging.
1126 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1128 default "9" if MAXSMP
1129 default "6" if X86_64
1130 default "4" if X86_NUMAQ
1132 depends on NEED_MULTIPLE_NODES
1134 Specify the maximum number of NUMA Nodes available on the target
1135 system. Increases memory reserved to accomodate various tables.
1137 config HAVE_ARCH_BOOTMEM
1139 depends on X86_32 && NUMA
1141 config ARCH_HAVE_MEMORY_PRESENT
1143 depends on X86_32 && DISCONTIGMEM
1145 config NEED_NODE_MEMMAP_SIZE
1147 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1149 config HAVE_ARCH_ALLOC_REMAP
1151 depends on X86_32 && NUMA
1153 config ARCH_FLATMEM_ENABLE
1155 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1157 config ARCH_DISCONTIGMEM_ENABLE
1159 depends on NUMA && X86_32
1161 config ARCH_DISCONTIGMEM_DEFAULT
1163 depends on NUMA && X86_32
1165 config ARCH_SPARSEMEM_DEFAULT
1169 config ARCH_SPARSEMEM_ENABLE
1171 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1172 select SPARSEMEM_STATIC if X86_32
1173 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1175 config ARCH_SELECT_MEMORY_MODEL
1177 depends on ARCH_SPARSEMEM_ENABLE
1179 config ARCH_MEMORY_PROBE
1181 depends on MEMORY_HOTPLUG
1186 bool "Allocate 3rd-level pagetables from highmem"
1187 depends on X86_32 && (HIGHMEM4G || HIGHMEM64G)
1189 The VM uses one page table entry for each page of physical memory.
1190 For systems with a lot of RAM, this can be wasteful of precious
1191 low memory. Setting this option will put user-space page table
1192 entries in high memory.
1194 config X86_CHECK_BIOS_CORRUPTION
1195 bool "Check for low memory corruption"
1197 Periodically check for memory corruption in low memory, which
1198 is suspected to be caused by BIOS. Even when enabled in the
1199 configuration, it is disabled at runtime. Enable it by
1200 setting "memory_corruption_check=1" on the kernel command
1201 line. By default it scans the low 64k of memory every 60
1202 seconds; see the memory_corruption_check_size and
1203 memory_corruption_check_period parameters in
1204 Documentation/kernel-parameters.txt to adjust this.
1206 When enabled with the default parameters, this option has
1207 almost no overhead, as it reserves a relatively small amount
1208 of memory and scans it infrequently. It both detects corruption
1209 and prevents it from affecting the running system.
1211 It is, however, intended as a diagnostic tool; if repeatable
1212 BIOS-originated corruption always affects the same memory,
1213 you can use memmap= to prevent the kernel from using that
1216 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1217 bool "Set the default setting of memory_corruption_check"
1218 depends on X86_CHECK_BIOS_CORRUPTION
1221 Set whether the default state of memory_corruption_check is
1224 config X86_RESERVE_LOW_64K
1225 bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
1228 Reserve the first 64K of physical RAM on BIOSes that are known
1229 to potentially corrupt that memory range. A numbers of BIOSes are
1230 known to utilize this area during suspend/resume, so it must not
1231 be used by the kernel.
1233 Set this to N if you are absolutely sure that you trust the BIOS
1234 to get all its memory reservations and usages right.
1236 If you have doubts about the BIOS (e.g. suspend/resume does not
1237 work or there's kernel crashes after certain hardware hotplug
1238 events) and it's not AMI or Phoenix, then you might want to enable
1239 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
1240 corruption patterns.
1244 config MATH_EMULATION
1246 prompt "Math emulation" if X86_32
1248 Linux can emulate a math coprocessor (used for floating point
1249 operations) if you don't have one. 486DX and Pentium processors have
1250 a math coprocessor built in, 486SX and 386 do not, unless you added
1251 a 487DX or 387, respectively. (The messages during boot time can
1252 give you some hints here ["man dmesg"].) Everyone needs either a
1253 coprocessor or this emulation.
1255 If you don't have a math coprocessor, you need to say Y here; if you
1256 say Y here even though you have a coprocessor, the coprocessor will
1257 be used nevertheless. (This behavior can be changed with the kernel
1258 command line option "no387", which comes handy if your coprocessor
1259 is broken. Try "man bootparam" or see the documentation of your boot
1260 loader (lilo or loadlin) about how to pass options to the kernel at
1261 boot time.) This means that it is a good idea to say Y here if you
1262 intend to use this kernel on different machines.
1264 More information about the internals of the Linux math coprocessor
1265 emulation can be found in <file:arch/x86/math-emu/README>.
1267 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1268 kernel, it won't hurt.
1271 bool "MTRR (Memory Type Range Register) support"
1273 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1274 the Memory Type Range Registers (MTRRs) may be used to control
1275 processor access to memory ranges. This is most useful if you have
1276 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1277 allows bus write transfers to be combined into a larger transfer
1278 before bursting over the PCI/AGP bus. This can increase performance
1279 of image write operations 2.5 times or more. Saying Y here creates a
1280 /proc/mtrr file which may be used to manipulate your processor's
1281 MTRRs. Typically the X server should use this.
1283 This code has a reasonably generic interface so that similar
1284 control registers on other processors can be easily supported
1287 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1288 Registers (ARRs) which provide a similar functionality to MTRRs. For
1289 these, the ARRs are used to emulate the MTRRs.
1290 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1291 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1292 write-combining. All of these processors are supported by this code
1293 and it makes sense to say Y here if you have one of them.
1295 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1296 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1297 can lead to all sorts of problems, so it's good to say Y here.
1299 You can safely say Y even if your machine doesn't have MTRRs, you'll
1300 just add about 9 KB to your kernel.
1302 See <file:Documentation/x86/mtrr.txt> for more information.
1304 config MTRR_SANITIZER
1306 prompt "MTRR cleanup support"
1309 Convert MTRR layout from continuous to discrete, so X drivers can
1310 add writeback entries.
1312 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1313 The largest mtrr entry size for a continous block can be set with
1318 config MTRR_SANITIZER_ENABLE_DEFAULT
1319 int "MTRR cleanup enable value (0-1)"
1322 depends on MTRR_SANITIZER
1324 Enable mtrr cleanup default value
1326 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1327 int "MTRR cleanup spare reg num (0-7)"
1330 depends on MTRR_SANITIZER
1332 mtrr cleanup spare entries default, it can be changed via
1333 mtrr_spare_reg_nr=N on the kernel command line.
1337 prompt "x86 PAT support"
1340 Use PAT attributes to setup page level cache control.
1342 PATs are the modern equivalents of MTRRs and are much more
1343 flexible than MTRRs.
1345 Say N here if you see bootup problems (boot crash, boot hang,
1346 spontaneous reboots) or a non-working video driver.
1351 bool "EFI runtime service support"
1354 This enables the kernel to use EFI runtime services that are
1355 available (such as the EFI variable services).
1357 This option is only useful on systems that have EFI firmware.
1358 In addition, you should use the latest ELILO loader available
1359 at <http://elilo.sourceforge.net> in order to take advantage
1360 of EFI runtime services. However, even with this option, the
1361 resultant kernel should continue to boot on existing non-EFI
1366 prompt "Enable seccomp to safely compute untrusted bytecode"
1368 This kernel feature is useful for number crunching applications
1369 that may need to compute untrusted bytecode during their
1370 execution. By using pipes or other transports made available to
1371 the process as file descriptors supporting the read/write
1372 syscalls, it's possible to isolate those applications in
1373 their own address space using seccomp. Once seccomp is
1374 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1375 and the task is only allowed to execute a few safe syscalls
1376 defined by each seccomp mode.
1378 If unsure, say Y. Only embedded should say N here.
1380 config CC_STACKPROTECTOR_ALL
1383 config CC_STACKPROTECTOR
1384 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1385 select CC_STACKPROTECTOR_ALL
1387 This option turns on the -fstack-protector GCC feature. This
1388 feature puts, at the beginning of functions, a canary value on
1389 the stack just before the return address, and validates
1390 the value just before actually returning. Stack based buffer
1391 overflows (that need to overwrite this return address) now also
1392 overwrite the canary, which gets detected and the attack is then
1393 neutralized via a kernel panic.
1395 This feature requires gcc version 4.2 or above, or a distribution
1396 gcc with the feature backported. Older versions are automatically
1397 detected and for those versions, this configuration option is
1398 ignored. (and a warning is printed during bootup)
1400 source kernel/Kconfig.hz
1403 bool "kexec system call"
1405 kexec is a system call that implements the ability to shutdown your
1406 current kernel, and to start another kernel. It is like a reboot
1407 but it is independent of the system firmware. And like a reboot
1408 you can start any kernel with it, not just Linux.
1410 The name comes from the similarity to the exec system call.
1412 It is an ongoing process to be certain the hardware in a machine
1413 is properly shutdown, so do not be surprised if this code does not
1414 initially work for you. It may help to enable device hotplugging
1415 support. As of this writing the exact hardware interface is
1416 strongly in flux, so no good recommendation can be made.
1419 bool "kernel crash dumps"
1420 depends on X86_64 || (X86_32 && HIGHMEM)
1422 Generate crash dump after being started by kexec.
1423 This should be normally only set in special crash dump kernels
1424 which are loaded in the main kernel with kexec-tools into
1425 a specially reserved region and then later executed after
1426 a crash by kdump/kexec. The crash dump kernel must be compiled
1427 to a memory address not used by the main kernel or BIOS using
1428 PHYSICAL_START, or it must be built as a relocatable image
1429 (CONFIG_RELOCATABLE=y).
1430 For more details see Documentation/kdump/kdump.txt
1433 bool "kexec jump (EXPERIMENTAL)"
1434 depends on EXPERIMENTAL
1435 depends on KEXEC && HIBERNATION && X86_32
1437 Jump between original kernel and kexeced kernel and invoke
1438 code in physical address mode via KEXEC
1440 config PHYSICAL_START
1441 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1442 default "0x1000000" if X86_NUMAQ
1443 default "0x200000" if X86_64
1446 This gives the physical address where the kernel is loaded.
1448 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1449 bzImage will decompress itself to above physical address and
1450 run from there. Otherwise, bzImage will run from the address where
1451 it has been loaded by the boot loader and will ignore above physical
1454 In normal kdump cases one does not have to set/change this option
1455 as now bzImage can be compiled as a completely relocatable image
1456 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1457 address. This option is mainly useful for the folks who don't want
1458 to use a bzImage for capturing the crash dump and want to use a
1459 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1460 to be specifically compiled to run from a specific memory area
1461 (normally a reserved region) and this option comes handy.
1463 So if you are using bzImage for capturing the crash dump, leave
1464 the value here unchanged to 0x100000 and set CONFIG_RELOCATABLE=y.
1465 Otherwise if you plan to use vmlinux for capturing the crash dump
1466 change this value to start of the reserved region (Typically 16MB
1467 0x1000000). In other words, it can be set based on the "X" value as
1468 specified in the "crashkernel=YM@XM" command line boot parameter
1469 passed to the panic-ed kernel. Typically this parameter is set as
1470 crashkernel=64M@16M. Please take a look at
1471 Documentation/kdump/kdump.txt for more details about crash dumps.
1473 Usage of bzImage for capturing the crash dump is recommended as
1474 one does not have to build two kernels. Same kernel can be used
1475 as production kernel and capture kernel. Above option should have
1476 gone away after relocatable bzImage support is introduced. But it
1477 is present because there are users out there who continue to use
1478 vmlinux for dump capture. This option should go away down the
1481 Don't change this unless you know what you are doing.
1484 bool "Build a relocatable kernel (EXPERIMENTAL)"
1485 depends on EXPERIMENTAL
1487 This builds a kernel image that retains relocation information
1488 so it can be loaded someplace besides the default 1MB.
1489 The relocations tend to make the kernel binary about 10% larger,
1490 but are discarded at runtime.
1492 One use is for the kexec on panic case where the recovery kernel
1493 must live at a different physical address than the primary
1496 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1497 it has been loaded at and the compile time physical address
1498 (CONFIG_PHYSICAL_START) is ignored.
1500 config PHYSICAL_ALIGN
1502 prompt "Alignment value to which kernel should be aligned" if X86_32
1503 default "0x100000" if X86_32
1504 default "0x200000" if X86_64
1505 range 0x2000 0x400000
1507 This value puts the alignment restrictions on physical address
1508 where kernel is loaded and run from. Kernel is compiled for an
1509 address which meets above alignment restriction.
1511 If bootloader loads the kernel at a non-aligned address and
1512 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1513 address aligned to above value and run from there.
1515 If bootloader loads the kernel at a non-aligned address and
1516 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1517 load address and decompress itself to the address it has been
1518 compiled for and run from there. The address for which kernel is
1519 compiled already meets above alignment restrictions. Hence the
1520 end result is that kernel runs from a physical address meeting
1521 above alignment restrictions.
1523 Don't change this unless you know what you are doing.
1526 bool "Support for hot-pluggable CPUs"
1527 depends on SMP && HOTPLUG
1529 Say Y here to allow turning CPUs off and on. CPUs can be
1530 controlled through /sys/devices/system/cpu.
1531 ( Note: power management support will enable this option
1532 automatically on SMP systems. )
1533 Say N if you want to disable CPU hotplug.
1537 prompt "Compat VDSO support"
1538 depends on X86_32 || IA32_EMULATION
1540 Map the 32-bit VDSO to the predictable old-style address too.
1542 Say N here if you are running a sufficiently recent glibc
1543 version (2.3.3 or later), to remove the high-mapped
1544 VDSO mapping and to exclusively use the randomized VDSO.
1549 bool "Built-in kernel command line"
1552 Allow for specifying boot arguments to the kernel at
1553 build time. On some systems (e.g. embedded ones), it is
1554 necessary or convenient to provide some or all of the
1555 kernel boot arguments with the kernel itself (that is,
1556 to not rely on the boot loader to provide them.)
1558 To compile command line arguments into the kernel,
1559 set this option to 'Y', then fill in the
1560 the boot arguments in CONFIG_CMDLINE.
1562 Systems with fully functional boot loaders (i.e. non-embedded)
1563 should leave this option set to 'N'.
1566 string "Built-in kernel command string"
1567 depends on CMDLINE_BOOL
1570 Enter arguments here that should be compiled into the kernel
1571 image and used at boot time. If the boot loader provides a
1572 command line at boot time, it is appended to this string to
1573 form the full kernel command line, when the system boots.
1575 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1576 change this behavior.
1578 In most cases, the command line (whether built-in or provided
1579 by the boot loader) should specify the device for the root
1582 config CMDLINE_OVERRIDE
1583 bool "Built-in command line overrides boot loader arguments"
1585 depends on CMDLINE_BOOL
1587 Set this option to 'Y' to have the kernel ignore the boot loader
1588 command line, and use ONLY the built-in command line.
1590 This is used to work around broken boot loaders. This should
1591 be set to 'N' under normal conditions.
1595 config ARCH_ENABLE_MEMORY_HOTPLUG
1597 depends on X86_64 || (X86_32 && HIGHMEM)
1599 config ARCH_ENABLE_MEMORY_HOTREMOVE
1601 depends on MEMORY_HOTPLUG
1603 config HAVE_ARCH_EARLY_PFN_TO_NID
1607 menu "Power management and ACPI options"
1609 config ARCH_HIBERNATION_HEADER
1611 depends on X86_64 && HIBERNATION
1613 source "kernel/power/Kconfig"
1615 source "drivers/acpi/Kconfig"
1620 depends on APM || APM_MODULE
1623 tristate "APM (Advanced Power Management) BIOS support"
1624 depends on X86_32 && PM_SLEEP
1626 APM is a BIOS specification for saving power using several different
1627 techniques. This is mostly useful for battery powered laptops with
1628 APM compliant BIOSes. If you say Y here, the system time will be
1629 reset after a RESUME operation, the /proc/apm device will provide
1630 battery status information, and user-space programs will receive
1631 notification of APM "events" (e.g. battery status change).
1633 If you select "Y" here, you can disable actual use of the APM
1634 BIOS by passing the "apm=off" option to the kernel at boot time.
1636 Note that the APM support is almost completely disabled for
1637 machines with more than one CPU.
1639 In order to use APM, you will need supporting software. For location
1640 and more information, read <file:Documentation/power/pm.txt> and the
1641 Battery Powered Linux mini-HOWTO, available from
1642 <http://www.tldp.org/docs.html#howto>.
1644 This driver does not spin down disk drives (see the hdparm(8)
1645 manpage ("man 8 hdparm") for that), and it doesn't turn off
1646 VESA-compliant "green" monitors.
1648 This driver does not support the TI 4000M TravelMate and the ACER
1649 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1650 desktop machines also don't have compliant BIOSes, and this driver
1651 may cause those machines to panic during the boot phase.
1653 Generally, if you don't have a battery in your machine, there isn't
1654 much point in using this driver and you should say N. If you get
1655 random kernel OOPSes or reboots that don't seem to be related to
1656 anything, try disabling/enabling this option (or disabling/enabling
1659 Some other things you should try when experiencing seemingly random,
1662 1) make sure that you have enough swap space and that it is
1664 2) pass the "no-hlt" option to the kernel
1665 3) switch on floating point emulation in the kernel and pass
1666 the "no387" option to the kernel
1667 4) pass the "floppy=nodma" option to the kernel
1668 5) pass the "mem=4M" option to the kernel (thereby disabling
1669 all but the first 4 MB of RAM)
1670 6) make sure that the CPU is not over clocked.
1671 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1672 8) disable the cache from your BIOS settings
1673 9) install a fan for the video card or exchange video RAM
1674 10) install a better fan for the CPU
1675 11) exchange RAM chips
1676 12) exchange the motherboard.
1678 To compile this driver as a module, choose M here: the
1679 module will be called apm.
1683 config APM_IGNORE_USER_SUSPEND
1684 bool "Ignore USER SUSPEND"
1686 This option will ignore USER SUSPEND requests. On machines with a
1687 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1688 series notebooks, it is necessary to say Y because of a BIOS bug.
1690 config APM_DO_ENABLE
1691 bool "Enable PM at boot time"
1693 Enable APM features at boot time. From page 36 of the APM BIOS
1694 specification: "When disabled, the APM BIOS does not automatically
1695 power manage devices, enter the Standby State, enter the Suspend
1696 State, or take power saving steps in response to CPU Idle calls."
1697 This driver will make CPU Idle calls when Linux is idle (unless this
1698 feature is turned off -- see "Do CPU IDLE calls", below). This
1699 should always save battery power, but more complicated APM features
1700 will be dependent on your BIOS implementation. You may need to turn
1701 this option off if your computer hangs at boot time when using APM
1702 support, or if it beeps continuously instead of suspending. Turn
1703 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1704 T400CDT. This is off by default since most machines do fine without
1708 bool "Make CPU Idle calls when idle"
1710 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1711 On some machines, this can activate improved power savings, such as
1712 a slowed CPU clock rate, when the machine is idle. These idle calls
1713 are made after the idle loop has run for some length of time (e.g.,
1714 333 mS). On some machines, this will cause a hang at boot time or
1715 whenever the CPU becomes idle. (On machines with more than one CPU,
1716 this option does nothing.)
1718 config APM_DISPLAY_BLANK
1719 bool "Enable console blanking using APM"
1721 Enable console blanking using the APM. Some laptops can use this to
1722 turn off the LCD backlight when the screen blanker of the Linux
1723 virtual console blanks the screen. Note that this is only used by
1724 the virtual console screen blanker, and won't turn off the backlight
1725 when using the X Window system. This also doesn't have anything to
1726 do with your VESA-compliant power-saving monitor. Further, this
1727 option doesn't work for all laptops -- it might not turn off your
1728 backlight at all, or it might print a lot of errors to the console,
1729 especially if you are using gpm.
1731 config APM_ALLOW_INTS
1732 bool "Allow interrupts during APM BIOS calls"
1734 Normally we disable external interrupts while we are making calls to
1735 the APM BIOS as a measure to lessen the effects of a badly behaving
1736 BIOS implementation. The BIOS should reenable interrupts if it
1737 needs to. Unfortunately, some BIOSes do not -- especially those in
1738 many of the newer IBM Thinkpads. If you experience hangs when you
1739 suspend, try setting this to Y. Otherwise, say N.
1743 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1745 source "drivers/cpuidle/Kconfig"
1747 source "drivers/idle/Kconfig"
1752 menu "Bus options (PCI etc.)"
1757 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1759 Find out whether you have a PCI motherboard. PCI is the name of a
1760 bus system, i.e. the way the CPU talks to the other stuff inside
1761 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1762 VESA. If you have PCI, say Y, otherwise N.
1765 prompt "PCI access mode"
1766 depends on X86_32 && PCI
1769 On PCI systems, the BIOS can be used to detect the PCI devices and
1770 determine their configuration. However, some old PCI motherboards
1771 have BIOS bugs and may crash if this is done. Also, some embedded
1772 PCI-based systems don't have any BIOS at all. Linux can also try to
1773 detect the PCI hardware directly without using the BIOS.
1775 With this option, you can specify how Linux should detect the
1776 PCI devices. If you choose "BIOS", the BIOS will be used,
1777 if you choose "Direct", the BIOS won't be used, and if you
1778 choose "MMConfig", then PCI Express MMCONFIG will be used.
1779 If you choose "Any", the kernel will try MMCONFIG, then the
1780 direct access method and falls back to the BIOS if that doesn't
1781 work. If unsure, go with the default, which is "Any".
1786 config PCI_GOMMCONFIG
1803 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1805 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1808 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1812 depends on X86_32 && PCI && ACPI && (PCI_GOMMCONFIG || PCI_GOANY)
1816 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1823 bool "Support mmconfig PCI config space access"
1824 depends on X86_64 && PCI && ACPI
1827 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1828 depends on X86_64 && PCI_MSI && ACPI && EXPERIMENTAL
1830 DMA remapping (DMAR) devices support enables independent address
1831 translations for Direct Memory Access (DMA) from devices.
1832 These DMA remapping devices are reported via ACPI tables
1833 and include PCI device scope covered by these DMA
1836 config DMAR_DEFAULT_ON
1838 prompt "Enable DMA Remapping Devices by default"
1841 Selecting this option will enable a DMAR device at boot time if
1842 one is found. If this option is not selected, DMAR support can
1843 be enabled by passing intel_iommu=on to the kernel. It is
1844 recommended you say N here while the DMAR code remains
1849 prompt "Support for Graphics workaround"
1852 Current Graphics drivers tend to use physical address
1853 for DMA and avoid using DMA APIs. Setting this config
1854 option permits the IOMMU driver to set a unity map for
1855 all the OS-visible memory. Hence the driver can continue
1856 to use physical addresses for DMA.
1858 config DMAR_FLOPPY_WA
1862 Floppy disk drivers are know to bypass DMA API calls
1863 thereby failing to work when IOMMU is enabled. This
1864 workaround will setup a 1:1 mapping for the first
1865 16M to make floppy (an ISA device) work.
1868 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1869 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1872 Supports Interrupt remapping for IO-APIC and MSI devices.
1873 To use x2apic mode in the CPU's which support x2APIC enhancements or
1874 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1876 source "drivers/pci/pcie/Kconfig"
1878 source "drivers/pci/Kconfig"
1880 # x86_64 have no ISA slots, but do have ISA-style DMA.
1889 Find out whether you have ISA slots on your motherboard. ISA is the
1890 name of a bus system, i.e. the way the CPU talks to the other stuff
1891 inside your box. Other bus systems are PCI, EISA, MicroChannel
1892 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1893 newer boards don't support it. If you have ISA, say Y, otherwise N.
1899 The Extended Industry Standard Architecture (EISA) bus was
1900 developed as an open alternative to the IBM MicroChannel bus.
1902 The EISA bus provided some of the features of the IBM MicroChannel
1903 bus while maintaining backward compatibility with cards made for
1904 the older ISA bus. The EISA bus saw limited use between 1988 and
1905 1995 when it was made obsolete by the PCI bus.
1907 Say Y here if you are building a kernel for an EISA-based machine.
1911 source "drivers/eisa/Kconfig"
1916 MicroChannel Architecture is found in some IBM PS/2 machines and
1917 laptops. It is a bus system similar to PCI or ISA. See
1918 <file:Documentation/mca.txt> (and especially the web page given
1919 there) before attempting to build an MCA bus kernel.
1921 source "drivers/mca/Kconfig"
1924 tristate "NatSemi SCx200 support"
1926 This provides basic support for National Semiconductor's
1927 (now AMD's) Geode processors. The driver probes for the
1928 PCI-IDs of several on-chip devices, so its a good dependency
1929 for other scx200_* drivers.
1931 If compiled as a module, the driver is named scx200.
1933 config SCx200HR_TIMER
1934 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
1935 depends on SCx200 && GENERIC_TIME
1938 This driver provides a clocksource built upon the on-chip
1939 27MHz high-resolution timer. Its also a workaround for
1940 NSC Geode SC-1100's buggy TSC, which loses time when the
1941 processor goes idle (as is done by the scheduler). The
1942 other workaround is idle=poll boot option.
1944 config GEODE_MFGPT_TIMER
1946 prompt "Geode Multi-Function General Purpose Timer (MFGPT) events"
1947 depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS
1949 This driver provides a clock event source based on the MFGPT
1950 timer(s) in the CS5535 and CS5536 companion chip for the geode.
1951 MFGPTs have a better resolution and max interval than the
1952 generic PIT, and are suitable for use as high-res timers.
1955 bool "One Laptop Per Child support"
1958 Add support for detecting the unique features of the OLPC
1965 depends on AGP_AMD64 || (X86_64 && (GART_IOMMU || (PCI && NUMA)))
1967 source "drivers/pcmcia/Kconfig"
1969 source "drivers/pci/hotplug/Kconfig"
1974 menu "Executable file formats / Emulations"
1976 source "fs/Kconfig.binfmt"
1978 config IA32_EMULATION
1979 bool "IA32 Emulation"
1981 select COMPAT_BINFMT_ELF
1983 Include code to run 32-bit programs under a 64-bit kernel. You should
1984 likely turn this on, unless you're 100% sure that you don't have any
1985 32-bit programs left.
1988 tristate "IA32 a.out support"
1989 depends on IA32_EMULATION
1991 Support old a.out binaries in the 32bit emulation.
1995 depends on IA32_EMULATION
1997 config COMPAT_FOR_U64_ALIGNMENT
2001 config SYSVIPC_COMPAT
2003 depends on COMPAT && SYSVIPC
2008 config HAVE_ATOMIC_IOMAP
2012 source "net/Kconfig"
2014 source "drivers/Kconfig"
2016 source "drivers/firmware/Kconfig"
2020 source "arch/x86/Kconfig.debug"
2022 source "security/Kconfig"
2024 source "crypto/Kconfig"
2026 source "arch/x86/kvm/Kconfig"
2028 source "lib/Kconfig"
git://ftp.safe.ca / safe / jmp / linux-2.6 / blob